Aircraft tires are subject to extreme operating conditions due to the heavy load per tire coupled with the high speed of the aircraft. Because of the heavy loading, the tires are subject to much greater deflection that passenger or truck tires.
Aircraft tires have two common constructions: bias and radial. Over 80% of aircraft tires are bias, which means they have a casing made of layers of alternate layers of ply that are at alternate angles substantially less than 90 degrees relative to the center line of the tread. However, radial tires are becoming more common as airframe manufacturers seek lighter weight. Radial tires are like passenger tires in that they have the ply oriented at substantially 90 degrees relative to the tread centerline. Aircraft tires come in a range of sizes, however the H size range has historically been a bias tire. Due to the modern trend, it is desired that radial aircraft tires are available in the H size. This has not been possible in the past because they have more deflection in the sidewall due to bending under loading. As a result, radial tires may have an increased heat generation and mechanical fatigue in the bead area of the tire. There may also be problems of bead cracking and scuffing in the bead region, as well as rubber deformation under the bead core.
Thus an improved radial tire with increased fatigue and bending resistance is desired.